"VENTILATION UNIT"

Technical field

This invention relates to a ventilation unit and to a shroud forming part of the ventilation unit.

The ventilation unit referred to in this specification is intended mainly for automotive applications, for cooling radiators and the like in motor-cars, lorries or the like.

Background art

Recent advances in automotive manufacturing have led to a considerable increase in the number of parts - which occupy more and more space- housed in the engine compartment of vehicles.

Moreover, on account of on-going technological developments, with a view to reducing fuel consumption and vehicle emissions, large quantities of heat need to be removed from the radiant masses in the engine compartments of vehicles.

To this must be added the fact that the engine compartment houses packs of radiators placed one in front of another to perform different functions.

Consider for example that the engine compartment may contain a water radiator, small radiators for the engine oil, for the air conditioning system, for the transmission, for cooling the catalytic converter, and others still, resulting in load losses along the radiator circuit.

In practice, the ventilation units are usually mounted between the engine and the radiators in more and more confined spaces and therefore must necessarily be as compact as possible but capable of generating powerful air flows.

The top surface dimensions of the electric fans, and thus of the ventilation units comprising them, are defined and, in practice, fixed by the dimensions of the radiator to be cooled, whilst the axial dimensions are determined by the axial dimensions of the electric motor.

To meet the requirements of high performance in confined spaces, prior art ventilation units tend to be either too large or too low-performing.

Disclosure of the invention

In this context, the main purpose of this invention is to overcome the above mentioned disadvantages.

One aim of the invention is to propose a ventilation unit whose dimensions are reduced compared to the prior art solutions.

Another aim is to propose a ventilation unit which is efficient in terms of fluid dynamics and control.

The stated technical purpose and aims are substantially achieved by a ventilation unit according to claim 1.

Brief description of drawings

Further features and advantages of the present invention are more apparent in the detailed description beiow, with reference to a preferred, non-limiting, embodiment of a ventilation unit, as illustrated in the accompanying drawings, in which:

Figure 1 is a schematic perspective view, partly exploded, of a ventilation unit according to the invention;

Figure 2 is a schematic plan view of the ventilation unit of Figure 1 ; Figure 3 is a schematic cross-section through line IN - III in Figure 2.

Detailed description of the preferred embodiments of the invention

With reference to the accompanying drawings, in particular Figure 1 , the numeral 1 denotes a ventilation unit according to this invention.

The ventilation unit 1 comprises an electric fan and a shroud 2 supporting the electric fan.

The electric fan basically comprises an electric motor 3 and an axial fan 4 driven by the electric motor 3 and having an axis of rotation R.

The electric motor 3, preferably a brushless motor with integrated electronic circuitry, and the fan 4 are described only insofar as necessary for defining and understanding this invention.

The electric motor 3 which drives the fan 4 comprises a casing 5a, a cap 5b coupled to the casing 5a to form a sealed enclosure 5 and, as mentioned, an electronic system 6 for the selfsame motor 3.

The electronic system 6 comprises electronic components of substantially known type and is partly housed in the enclosure 5.

in other words, according to the invention, the electronic control system 6 for the electric motor 3 is located partly inside of the enclosure 5 and partly outside of it, that is to say, it comprises electronic components mounted inside the motor 3 and other electronic components mounted outside the motor 3, as explained in more detail below.

With reference in particular to Figures 1 and 3, the reference numeral 6 denotes, for simplicity, the part of the electronic system located outside the motor 3.

The shroud 2, also described only insofar as necessary for defining and understanding the invention, supports the electric fan by means of the motor 3.

The shroud 2 comprises an outer frame 7, which in the example illustrated is substantially cylindrical in shape, and which, generally speaking, is fixable to a vehicle, that is to say, is used to mount the ventilation unit 1 to a generic vehicle.

The shroud 2 comprises a fastening element 8 for fixing the motor 3.

The fastening element 8 is in the form of a collar and is on the inside of the outer frame 7 and coaxial therewith.

In other words, the collar 8 is closer to the axis R than the outer frame 7. The shroud 2 comprises a plurality of spokes 9 connecting the outer frame 7 to the fastening element 8.

As illustrated, the spokes 9 comprise a spoke 10 with a compartment 1 1 for housing part of the electronic control system 6 for the electric motor 3.

In practice, the spoke 10 comprises housing means for electronic components 12, 3 which form part of the electronic system 6 and which, as mentioned, are mounted on the outside of the enclosure 5 of the motor 3. More precisely, in the example illustrated, the components mounted outside the enclosure 5 are an electrolytic filter capacitor 12 and a filter inductor 13, that is, electronic filter components.

The electrolytic capacitors normally forming part of the electronic circuitry integrated in brushless motors are, together with filter inductors, much larger than all the other components and placing them outside the enclosure 5 advantageously allows the dimensions of the enclosure to be reduced.

In practice, electrolytic capacitors and inductors are in the order of twenty or more millimetres in size, whilst the other components are just a few millimetres in size.

Also, placing them outside the casing facilitates cooling of the components 12 and 13 because it exposes them to ambient temperature and not to the operating temperature inside the motor, which is much higher also on account of all the other power components.

In the preferred embodiment illustrated, the housing compartment 11 is formed directly in the spoke 10.

More precisely, the spoke 10 itself defines a housing which comprises the compartment 1 1.

In the embodiment illustrated, the spoke 10 is aiso shaped in such a way as to define a housing for a power cable 14 of the motor 3.

In other words, the housing defined by the spoke 10 comprises the compartment 1 1 .

With reference in particular to Figure 3, it may be observed that the compartment 1 1 is located near the inner collar 8.

Thus, the compartment 11 does not reduce the performance of the fan 4. In effect, the axial fan 4, being of axial type, is most effective at its outer half, towards the frame 7. Thus, placing the compartment 1 1 , and hence the components 12, 13 it houses, near the collar 8, is aiso advantageous from the fluid dynamic viewpoint since the effect produced on the flow generated by the operation of the fan is negligible.

In addition, the electrolytic capacitor 12 in particular is housed in the compartment 11 and placed near the power components inside the enclosure 5. That way, the connecting inductance created by the connecting cables 18 extending between the power components inside the motor and the capacitor 12 outside it is negligible and does not create disturbances at high frequencies,

With reference in particular to Figures 1 and 3, it may be observed that the compartment 11 extends mainly in a direction parallel to the axis of rotation R, transversal to the main direction of extension of the spoke 10.

Advantageously, the capacitor 12 is mounted in the compartment 11 in such a way that its main direction of extension is parallel to the main direction of extension of the compartment 11 itself.

As illustrated, the main directions of extension of the electrolytic capacitor 12 and of the compartment 1 1 are both parallel to the axis of rotation R of the fan 4,

Along that axis of rotation the size of the compartment 11 is comparable to the size of the collar 8 along the same axis of rotation so as to maximize the capacity of the selfsame compartment 1 .

With reference to the inductor 13, it may be observed that the inductor is mounted in the spoke 10 in such a way that its main direction of extension is parallel to the main direction of extension of the selfsame spoke 10.

The spoke 10 extends between the collar 8 and the frame 7 and has a grooved profile or groove 15 which defines the housing for the components

12 and 13 and for the passage of the power cable 14.

Near the collar 8 the groove 15 widens to form the compartment 11 in which the capacitor 12 is preferably mounted.

A closing partition 16 is provided in the groove 15, between the collar 8 and the frame 7. The partition 16 has an opening 16a allowing the cable 14 to pass through. The electronic components 2 and 13 are mounted in the spoke 10 between the collar 8 and the partition 16.

The power cable 14 leads out of the enclosure 5 into the spoke 10 and through the partition 16 and is free to be connected to a power source not illustrated.

The ventilation unit 1 comprises a cover 17 which closes the part of the spoke 10 which houses the electronic components 12 and 13.

The cover 17 extends radially between the collar 8 and the partition 16 across the full width of the spoke 10 in order to protect the electronic components 12 and 13.

Preferably, the cover 17 is sealed to the spoke 10, for example by means of resins, in order to protect the components 12 and 13.

In practice, the compartment 11 which houses the electronic components 12 and 13 is sealed also by the cover 17 so that the components are protected even in heavy-duty application.

Advantageously, the cover 17 is shaped to cover also the connecting cables 18 so that the latter, too, are hermetically protected.

The invention has important advantages.

The greater the power and size of the motor, the larger is the axial dimension of the collar which supports the motor.

Taking advantage of the axial length of the collar, it is possible to mount the capacitor, which is usually longer than it is wide, vertically, parallel to the axis of rotation, using the full axial length of the spoke in the vicinity of the collar. it should be noted that of all the components, the electrolytic capacitor is the one most sensitive to temperature and prone to deterioration in terms of durability and dependability and it is therefore advantageous for it to work at a low temperature.

The inductor has a highly resistive property and therefore tends to generate heat but, since it is mounted in the spoke, does not affect the temperature of the capacitor. Since the capacitor and the inductor are mounted outside the motor, inside a spoke, they are exposed directly to external air and are not affected by the temperature inside the motor but, at the same time, do not disturb the air flow produced by the fan,

Inside the motor, the other power and signal components can be optimized because there is more space available for them even if the enclosure is smaller in size than in prior art solutions.

Moreover, the back of the motor, which acts as a heat sink, is also optimized for cooling the signal components and for the MOSFETs usually present in the electronic control system.